1. Field of the Invention
The invention relates to cosmetic compositions, such compositions in order to inhibiting darkening of the skin and initiates the stimulation of collagen synthesis.
Azelaic acid may be used as therapeutic agent in the treatment of skin disorders and also have whiting effect. Azelaic acid is very polar due to the two carboxyl groups. Because of this polarity, skin penetration is very low. The inventive molecules that combine with one or two hydrophilic headgroups connected by a hydrophobic spacer can increase skin penetration.
Enzymatic synthesis is widely using in various industrial scopes such as cosmetics, fine chemicals, pharmaceuticals and food ingredients. Lipase-catalyzed reactions are superior to conventional chemical methods owing to mild reaction conditions, high catalytic efficiency and the inherent selectivity of natural catalysts, which results in much purer products.
2. Description of the Prior Art
L-ascorbic acid is a well-know water-soluble antioxidant that has whitening effect and serves as a cofactor of prolinehydroxylase to promote synthesis of collage (Quaglino, D. Jr., et al., J. Biol. Chem., p 272-345, 1997). L-ascorbic acid is also used in various products requiring a long-term antioxidation effect. But its unfulness for such products is not so reliable because it is sensitive to heat light and air. As a result, many studies have been made on the development of ascorbic acid derivatives with enhanced stability while maintaining the antioxidation activity. Notably, a common way to improve the stability of L-ascorbic acid is converting a 2- or 3-hydroxyl group of L-ascorbic acid to another subsistent (U.S. Pat. No. 6,444,144; 5,143,648; 4,780,549; and 4,177,455, Japan Pat. Sho 52-18191, and Korean Pat. No. 91-8733).
The novel ascorbic acid derivative 3-O-ethyl-ascorbic acid is a structurally stabile ascorbic acid and effective whitening agent that can it the polymerization arising due to the biological dihydroxyindole in vivo caused by ultraviolet rays (U.S. Pat. No. 6,861,050). This novel ascorbic acid derivative is metabolized by the human body in the same manner as regular ascorbic acid and it's soluble in water as well as oil, making it optimal for use in cosmetics.
Azelaic acid is a naturally occurring nine carbon straight chain molecule with two terminal carboxyl groups. Azelaic acid is an anti-keratinizing agent, displaying antiproliferative effects on keratinocytes and modulating the early and terminal phases of epidermal differentiation (Passi, et al. G. Ital. Dermatol. Venerol. 1989, 124(10):455-463). Azelaic acid is a competitive inhibitor of the reduction of testosterone to dihydrotestosterone, and as such is supposed to reduce the production of sebum in the sebaceous gland. Furthermore, recent investigations gave demonstrated that azelaic acid and seba-structure-activity relationship studies gave revealed that these effects are retained when the dicarboxylic acid has a backnone of about 2 to 10 carbons (U.S. Pat. No. 6,180,669).